Terpene alcohol, ester thereof and process for making same



Jan. 22, 1963 J. H. BLUMENTHAL 3,075,003

TERPENE ALCOHOL ESTER THEREOF AND PROCESS FOR MAKING SAME 2 Sheets-Sheet 1 Filed May 21, 1959 Q EOBWMEQQD QMGE 23 WZOWGQQ hhMZkui 1N nibn: MWTI MC TQQLQ MEMU M so? Rm INVENTOR n JICKHBLuME/VrH/JL.

J. H. BLUMENTHAL TERPENE ALCOHOL ESTE Jan. 22, 1963 R THEREOF AND PROCESS FOR MAKING SAME 2 Sheets-Sheet 2 Filed May 21, 1959 Jim/(H BLUMENTHAL.

MMWMA 4 United States Patent 9 3,075,003 TERPENE ALCOHOL, ESTER THEREOF AND PROCESS FOR MAKING SAME Jack H. Blumenthal, New Monmouth, N.J., assignor to International Flavors & Fragrances, Inc., New York,

N.Y., a corporation of New York Filed May 21, 1959, Scr. No. 814,912 Claims. (Cl. 260-488) This invention relates to a process for making the terpene alcohol 2-methyl-6-methylene-7-octene-2-ol, and to the acetate thereof.

The trivial name myrcenol has been used by various prior workers to designate substances having widely varying compositions. In no case was it used to designate the pure material Z-methyl-6-methylene-7-octene-2-ol. One of the materials so designated appears in the patent to Booth, No. 2,871,271, wherein the material is actually assigned the structure 2-methyl-6-methylene-7-octene-2- 01. This composition is actually a mixture containing other materials to the extent of about 50%. Compositions described by other prior workers in the art under the name myrcenol are even more remote from 2- methyl-6-methylene-7-octene-2-ol in their composition. We therefore avoid the use of the abused term my-reenol and are designating 2-methyl-6-methylene-7-octene- 2-ol by the short term myrcene hydrate.

The principal object of the present invention is to obtain the pure alcohol 2-methyl-6-methylene-7-octene-Z-ol and its derivatives such as the esters, and to provide a simple, efiicient process for the production thereof.

The invention accordingly comprises the novel products and intermediates thereof, as well as the process and steps of process according to which such products are manufactured, the specific embodiments of which are described hereinafter by way of example and in accordance with which I now prefer to practice the invention.

In practicing the invention I react myrcene with sulfur dioxide to produce myrcene sulfone, and then hydrate the myrcene sulfone to produce myrcene sulfone hydrate. This myrcene sulfone hydrate is then decomposed by heating it to liberate sulfur dioxide, and thereby to produce the compound 2-methyl-6-methylene-7-octene-Z-ol in pure form. The sulfur dioxide is the usual product which is substantially anhydrous. The myrcene is a commercial product ordinarily found on the market containing approximately 75% myrcene together with other terpenes, notably dipentene, as impurities.

Commercial myrcene in the presence of about 1% f an inhibitor such as hydroquinone, Ionol, phenyl-flnaphthylamine, etc., to prevent polymerization and polysulfone formation, is stirred with an excess of sulfur dioxide in a closed vessel at 60 to 100 C. at autogenous pressure over a period of 2-6 hours. After cooling and removal of the excess S0 any unreacted material is removed by stripping, viz., distillation under vacuum. The reaction occurring as above indicated is as follows:

Myrcene sulfone The crude sulfone is then hydrated at the isopropylidene double bond by stirring with one and a half to three times its weight of 4060% sulfuric acid at 10-25 C., over a period of one-half to three hours. The reaction mixture is diluted with water and then neutralized with Ice 2 sodium hydroxide. The oil layer is separated with the aid of a solvent such as benzene, and the solvent removed under vacuum.

The reaction occurring here is:

Myrcene sulfone hydrate I The crude s-ulfone hydrate is then decomposed by heating under vacuum at to C. to obtain the desired hydrate, 2-methyl-6-methylene-7-octene-2-ol, in an overall yield of 70% of theory based on the myrcene content of the commercial myrcene used. It is evident that this process can be conducted in a continuous man nor as well as in discrete steps as herein described.

Although not absolutely required, when decomposing large quantities we may conduct the decomposition of the sulfone hydrate in the presence of 1 to 2% of a high boiling organic base such as triethanolamine or Primene 1M (Rohm & Haas), which is a mixture of tertiary alkylamines. Weak inorganic bases such as CaCO may be also used.

The reaction occurring here is:

r CEz--CCHzCHz-Cl1z-C=CH l Heat OH H2O OH:

Myrcene sulfone hydrate $113 (EH2 CHz-C-CHz-CHz-CHz-CCH=CH2 Myi-cene hydrate The product obtained is a water-white liquid having the characteristics mentioned below, which is 2-methyl-6- methylene-7-octene-Z-ol. The intermediate products are: (a) the myrcene sulfone, which in its crude state is a brown oily liquid Whose vcharacteristics will very over a relatively wide range depending on the amount of polymer present and on the efficiency of the stripping operation. its characteristics in both the crude and refinedv states are given below. The crude myrcene sulfone may be used in the step for producing the sulfone hydrate without purification; and (b) the myrcene sulfone hydrate, which in its crude state is an orange colored viscous oil whose density and refractive index will also vary over a relatively wide range depending on the pres-. ence of polymer and the efficiency of the stripping opera-- tion. Its characteristics in the crude and refined states are given below. It is not necessary that the pure sulfonehydrate be employed for the step of producing the pure Z-methyl-6-methylene-7-octene-Z-ol.

The following are examples of the manner in which I now prefer to produce the products of my invention. It is understood that these examples are purely illustra-f tive, and the invention is not to be considered as restricted thereto except as indicated in the claims.

The myrcene used (approximately 75 myrcene) in the examples below is the aforesaid usual product of commerce obtained from the pyrolysis of fi-pinene, and contains other terpenes, notably dipentene, as impurities.

. umn 311C1 3. water COHdeHSEI.

EXAMPLE 1 perature of 82 C. The weight of the residue was 1322 grams, and by analysis consisted of 95% myrcene sulfone. Yield: 94.5% of theory (based on myrcene content of commercial myrcene). The crude sulfone was fractionatedin a wiping still (Rodney Hunt Machine Co.) with final pressure and temperature at 20-30 microns vacuum and 80-90 C. Characteristics of the distilled myrcene sulfone, at least 99% pure, are as follows: very pale yellow heavyoil, ND 1.5069, D 1.0985, waterinsoluble, generally soluble in usual organic solvents;

limitedisolubilityin hydrocarbon solvents, sulfur 15.9%

obtained, theoretical 16.0%.

B. Hydration of Myrcene Sulfone 400 grams of crude myrcene sulfone as prepared in Example 1, A, was stirred vigorously'with 1200 grams of 50% (by weight) sulfuric acid for a period of one-half hourat 20 C. The reaction mass was added to 2400 cc of: cold'water and some polymeric material was separated and discarded. The'acid was carefully neutralized to pH 8 with sodium hydroxide while keeping thetemperaturefl below 50 C., with cooling andgood stirring. The oil layer'which formed was separated with the aid of some benzene and the water layer was extracted with additional benzene. The benzene solutions were combined and the benzene plus traces of water were-removed under a vacuum of mm. to a pot temperature of 70 C. The weight. of the residue (crude sulfone hydrate) was 384' grams, and by analysis consisted of 93% of the sulfone hydrate. Yield 86% of theory (based on myrcene sulfone used). The crude myrcene sulfone hydrate was distilled in said wiping still with final pressure and temperature: at -20.microns vacuum and 90-95 C., and the distilled myrcene sulfone hydrate was at least 98.5% pure. Its characteristics are as follows: pale yellow viscous oil ND 1.5020, D 3 1.1500; partially soluble in water at ,C-.; soluble in ether and in benzene; insoluble in hexane; sulfur 14.5% obtained, theoretical 14.68%.

C. Decomposition of Myrcene sulfone Hydrate and Producti'om ,of Z-Methyl-6-Methyiene-7-Octene-2-Ol 96 grams of the sulfone hydrate prepared as in Example 1,B, was placed in a 200 ml. flask fittedwith a short col- The pot temperature was brought to 140-160" C., and the myrcene hydrate distilled'over at 85-100" C. at a vacuum of 24 mm. The

distillate weighed 57 grams, and after being freed of traces ofzsulfur dioxide by purging with nitrogen had a refractive index of ND 1.4729, The gas-liquid partition chromatogram (GLPC) showed a purity of over 98%. Yield 88.5% of theory, based on myrcene sulfone hydrate used. The 2% impurity was mainly myrcene with no other'alcd- 1101 present. Redistillation gave a pure water-white liquid product (as shown by the GLPC) B.P. 78 C. (5 mm.) ND" 1.4731, D 0.8711, MR 49.60, 'MR 48.98. The product has a fresh, slightly lim ey, flowery odor. The

a product is 2-methyl-6-methylene-7-octene 2 ol.3

Since Z-methyl-6 methylene-7-octene-2-ol polymerizes readily, it should be'protected at all times with an inhibitor suchT-as' hydroquinone, Ionol, phenyl-p-naphthylamine, etc... I

When working on a larger scale a continuous rum-film evaporator is preferred for the decomposition to minimize the formation of by-odors. A dilute caustic wash, followed'by a water wash, is also effective for the same purpose.

The reaction masswas cooled and the excess I I am also the first to {3, EXAMPLE 2.-PREPARATION OF ACETATE OF MYRCENE HYDRATE 750 grams of acetic anhydride and 5.0 grams of phosphoric acid are placed in a suitable flask and heated to 40 C. .To this solution at 40 C. there is added over a period of 1-2 hours, 500 grams of 2-methyl6-methylene- 7-octene-2-ol (containing 1% Ionol). After stirring for one additional hour after the completion of addition, sodium bicarbonate is added to neutralize the phosphoric acid, and stirring is continued for one hour. The mass is then treated with two volumes of Water with stirring for 30 minutes, and the oil which separates is washed neutral with sodiumlbica rbonate solution. Fractionation of this washed oil at 0.5 mm. yields 450 grams of the acetate of 2- methyl-6-methylene-7-octene-Z-ol, a water-white liquid boiling at 53 C., and having a refractive index of ND 1.4590, and a density of D 3 0.9100. The ester tests 99.4% bysaponification. It should be protected with one of the usual polymerization inhibitors, as mentioned in Example 1, C. The odor is an individual fresh, woody cologne odor, with a mossy undertone.

In addition to the characteristics of the compound 2- rnethyl-6-methylene-7-octene-Z-ol given above, further and complete proof of the composition is discussed below, and is shown in the accompanying drawings, in which:

FIG. 1 represents an infrared spectrogram of Z-methyl- 6-methylene-7-octene-2-ol;

FIG. 2 is a gas-liquid partition chromatographic curve thereof, and

FIG. 3 is an ultravioletspectrogram thereof.

Referring to FIG. 1, the infrared spectrum of 2-methyl- 6-methylene-7-octene-2-ol has a very strong absorption centered around 900 cm.- and a peak at 990* indicating the presence of a vinyl and vinylidene group, and two peaks at 1600 cm.- and 1635 cmr indicating conjugated double bonds. Similar peaks, with about the same intensities are also found in myrcene. The myrcene hydr'ate also has a large hydroxyl absorption at 3330 cm.- and absorption peaks in the tertiary hydroxyl region at 1125, 1150v and 1200 cmr as well as another peak at 943 cm which are not present in myrcene.

Referring to FIG. 2, the gas-liquid partition chromatogram of'the new myrcene hydrate showed only one peak, this indicating the absence of impurities. The new hydrate absorbed two moles of hydrogen, indicating the presence of two double bonds, to yield a saturated alcohol which had the following physical constants: B.P. 85 C. (9 mm.), ND 1.4334, D 0.8262, phenyl urethane M.P. 85.886.2 C. Almost identical physical constants were reported by Houlihan, J. Org. Chem., 23, 689 (1958) for 2,6-dimethyl-2-octanol. Thus there is no question that the carbon skeleton and position of the hydroxyl group of the new hydrate is established.

7 Referring to FIG. 3, the ultraviolet absorption maximum is shown at 2240 A. in iso-octane, with an epsilon (extinction coeflicient) of 18,826. Contrasting this coeflicient with that reported by Booth in Patent No. 2,871,-, 271, we fin'd that Booth reports an epsilon of 9600 for his material. Comparison of these ultra-violet extinction values shows thatBooths value is a little more than half that of the pure 2-methyl-G-methylene-7-octene-2-ol, and accordingly the Booth figure shows a mixtureof materials, no one of which was present in the proportion of more than about 51%.

So far. as I am aware, I am accordingly the first to produce pure Z-methyl-6-methylene-7-octene-2-ol, and I am the first to determine that this pure product is a perfume material having the odor given. I have thus established that the odor is due to Z-methyl-6-methylene-7-octene-2-ol, and not to impurities occurring therewith, and which are present in compounds such as those mentioned by Booth.

produce the acetate of myrcene hydrate. 5

I claim: 1. A process which comprises reacting myrcene with sulfur dioxide to produce myrcene sulfone, hydrating the myrcene sulfone to produce myrcene sulfone hydrate, and decomposing the myrcene sulfone hydrate with heat to liberate sulfur dioxide and to produce 2-methy1-6-methylene-7-octene-2-o1.

2. A process which comprises treating myrcene sulfone with an aqueous acid capable of hydrating said sulfone to produce myrcene sulfone hydrate, and heating the myrcene sulfone hydrate at a temperature sufiicient to liberate sulfur dioxide to produce 2-methyl-6-methylene-7-octene-2- ol.

3. A process which comprises treating myrcene sulfone in the presence of aqueous sulfuric acid to produce myrcene sulfone hydrate, and heating the myrcene sulfone hydrate at a temperature suflicient to liberate sulfur dioxide to produce 2-methyl-6-methylene-7-octene-2-ol.

4. A process which comprises reacting myrcene with anhydrous sulfur dioxide in the presence of a polymerization inhibitor to produce myrcene sulfone, reacting the myrcene sulfone with aqueous sulfuric acid to produce myrcene sulfone hydrate, and heating the myrcene sulfone hydrate at a temperature suflicient to liberate sulfur dioxide to produce Z-methyl-6-methylene-7-octene-2-ol.

5. The acetate of myrcene hydrate prepared from substantially pure 2-methyl-6-methylene-7-octene-2-ol having the infrared spectrogram shown in FIG. 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,481,669 Hull et a1 Sept. 13, 1949 2,640,834 Tewksbury et a1 June 2, 1953 2,794,826 Bell June 4-, 1957 2,810,728 Beesley et a1 Oct. 22, 1957 2,806,887 Surmatis Sept. 17, 1957 2,871,271 Booth Ian. 27, 1959 2,902,510 Webb Sept. 1, 1959 2,935,526 Bain May 3, 1960 

5. THE ACETATE OF MYRCENE HYDRATE PREPARED FROM SUBSTANTIALLY PURE 2-METHYL-6-METHYLEN-7-OCTENE-2-OL HAVING 